Many tasks can be envisioned wherein it is either desired or required to impose a particular force against a workpiece at a predetermined position or location. It may be of extreme importance for the proper accomplishment of the task that the force have a particular magnitude and that it be applied with a specific orientation for a prescribed duration. For those tasks which require precision and accuracy during the application of very specific forces, or the combined application of variable forces in different directions, it is particularly important that the forces be properly controlled.
In recent years it has become widely appreciated that voice coil actuators can be used for precise and accurate work in many different applications where extremely small forces are used and extremely small tolerances are required. For example, such a voice coil actuator is disclosed and claimed in U.S. Pat. No. 5,175,456 which issued to Neff et al. for an invention entitled "Workpiece Transporter", and which is assigned to the same assignee as the present invention. Further, it is known that voice coil actuators are well suited for moving a work probe in translation, z, and rotation, .theta., in plane translation, x-y, and various combinations of these movements. For example, a notice of allowance has been received for U.S. application Ser. No. 08/620,504 which was filed by Neff et al. on Mar. 22, 1996 for an invention entitled "Actuator for Translational and Rotary Movement" and which is assigned to the same assignee as the present invention.
Recognizing there are many separate and distinct tasks which can be accomplished by a work probe, and specifically one that is moveable with extreme accuracy and precision in both translation and rotation, the issue becomes one of control. In order to control a work probe in any particular application, it is first useful to properly position the work probe in a start position. For work probes of a voice coil actuator, this start position will be defined by an axial position, z, and an angular orientation, .theta.. From this start position, the forces, positions, and the movements of the probe will be dictated by the particular task to be performed. Regardless whether the probe is required to measure, test, move, alter, adjust, verify, or perform any combination of these type functions on a workpiece, it is recognized that a high degree of control is required.
In light of the above it is an object of the present invention to provide computer/controller processes for a voice coil actuator, and a method for its use, which precisely moves the probe of the actuator in combinations of translation and rotation in accordance with preprogrammed sequences along and around various control axes. It is another object of the present invention to provide computer/controller processes for a voice coil actuator, and a method for its use, which selectively moves the probe of the actuator in translation or rotation, and selectively applies linear or rotational forces on a workpiece, in accordance with task requirements. Yet another object of the present invention is to provide computer/controller processes for a voice coil actuator, and a method for its use, which can be programmed by the operator to accomplish a specific task, and then subsequently re-programmed to accomplish additional tasks. Another object of the present invention is to provide a computer/controller for a voice coil actuator which is relatively easy to manufacture, is simple to use, and is comparatively cost effective.